In a Cooperative Multi-Input Multi-Output (Co-MIMO) system, a Base Station (BS) obtains Channel State Information (CSI) of a Mobile Station (MS), and communicates with the MS through a Space Division Multiple Access (SDMA) technology according to the CSI.
In distributed Co-MIMO systems in the prior art, the cooperative BSs do not exchange real-time CSI or statistical CSI with each other, and the precoding matrix of each BS is calculated according to the real-time local CSI only. This scheme is not limited by the backhaul delay or capacity. Because it is not necessary to process CSI in a centralized way, higher extensibility is realized. Moreover, the distributed Co-MIMO scheme is closer to the existing cellular network architecture, and the involved protocol modification is relatively simple. However, the distributed Co-MIMO system in the prior art are mostly applied in single-user, multi-antenna scenarios or multi-user, single-antenna scenarios. In a multi-user, multi-antenna scenario, the number of antennas of each BS needs to be greater than the total number of antennas of the MSs served by the BS, which obviously restricts the application of the scheme.